A CT scan system with a compressing unit that compresses the data acquired by means of an X-ray source, before the data is being transmitted to a central processing unit. The data compressing unit utilizes an entropy coding method for data compression. Four arrays of sensors are being used in one reading to create the data with a certain periodicity superimposed to the matrix of data that must be taken into account to achieve significant compression improvements. The present invention yields compression rates in the range of 20% to 30% while maintaining fast operation.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A computer tomography apparatus comprising: an X-ray source which emits an X-ray beam from a focus, at least said focus being rotatable around an axis; a radiation detector having four rows of detector elements disposed in successions along said axis and extending substantially transversely to said axis, said X-ray source and said radiation detector being adapted to receive an object therebetween as said focus rotates so that said radiation detector generates measurement data representing X-rays in said beam attenuated by the object, said measurement data being organized as respective entries Xij in a matrix having i rows and j columns; a data compression unit supplied with said measurement data which compresses said measurement data using a prediction algorithm which produces predicted values, followed by an entropy encoding the predicted values, to produce compressed data, said data compressing unit when executing said prediction algorithm for an entries Xij in row i, using entries X(i 4)j in row (i 4) of said matrix; an image computer supplied with said compressed data, said image computer decompressing said compressed data to recover said measurement data and producing image data therefrom representing an image of said object; and a display supplied with said image data for visually displaying said image.
2. A computer tomography apparatus according to claim 1 , further comprising; a noise reduction unit supplied with said measurement data, said noise reduction unit produces noise-reduced measurement data by performing a noise reduction technique on said measurement data.
3. A computer tomography apparatus according to claim 1 , wherein said data compression unit comprises a Golomb-Rice encoder for said entropy encoding.
4. A computer tomography apparatus according to claim 1 , wherein said data compression unit comprises a Huffman encoder for said entropy encoding.
5. A computer tomography apparatus according to claim 1 , wherein said data compression unit comprises an Arithmetic encoder for said entropy encoding.
6. A computer tomography apparatus according to claim 1 , wherein said data compression unit comprises an Run length encoder for said entropy encoding.
7. A computer tomography apparatus comprising: an X-ray source which emits an X-ray beam from a focus, at least said focus being rotatable around an axis; a radiation detector, said radiation detector and said X-ray source being adapted to receive an object therebetween as said focus rotates so that said radiation detector generates measurement data representing X-rays in said beam attenuated by the object, said measurement data being organized as respective entries Xij in a matrix having i rows and j columns; a noise reduction unit supplied with said measurement data which performs a noise reduction technique on said measurement data to produce noise-reduced measurement data; a data compression unit supplied with said noise-reduced data which compresses said noise-reduced data by executing a prediction algorithm on said noise-reduced data to produce predicted values, followed by entropy encoding the predicted values thereby producing compressed data, said data compressing unit when executing said prediction algorithm for an entries Xij in row i, using entries X(i 4)j in row (i 4) of said matrix; an image computer supplied with said compressed data, said image computer decompressing said compressed data to recover said measurement data and producing image data therefrom representing an image of said object; and a display supplied with said image data for visually displaying said image.
8. A computer tomography apparatus according to claim 7 , wherein; the noise reduction technique is being executed for the entries Xij using a median of entries X(i 1), Xi, X(i 1) in a preceding row instead of entries Xi in the preceding row; and a Golomb-Rice coding method is utilized for entropy encoding of the predicted values.
9. A computer tomography apparatus according to claim 7 , wherein said data compression unit comprises a Golomb-Rice encoder for said entropy encoding.
10. A computer tomography apparatus according to claim 7 , wherein said data compression unit comprises a Huffman encoder for said entropy encoding.
11. A computer tomography apparatus according to claim 7 , wherein said data compression unit comprises an Arithmetic encoder for said entropy encoding.
12. A computer tomography apparatus according to claim 7 , wherein said data compression unit comprises an Run length encoder for said entropy encoding.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
July 13, 2001
October 22, 2002
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